Transformer spin-triplet superconductivity at the onset of isospin order in bilayer graphene

被引:28
作者
Dong, Zhiyu [1 ]
Chubukov, Andrey, V [2 ]
Levitov, Leonid [1 ]
机构
[1] MIT, Dept Phys, Cambridge, MA 02139 USA
[2] Univ Minnesota, WI Fine Theoret Phys Inst, Minneapolis, MN 55455 USA
基金
美国国家科学基金会;
关键词
TRANSITION-TEMPERATURE; STATE; FERMIONS;
D O I
10.1103/PhysRevB.107.174512
中图分类号
T [工业技术];
学科分类号
08 ;
摘要
We consider the origin of superconductivity found recently in Bernal bilayer graphene at the onset of isospin-polarized order, trying to infer the pairing mechanism and superconducting order from the measurements available to date. The superconductivity is induced by a parallel magnetic field and persists well above the Pauli limit, indicating an unconventional scenario of quantum-critical pairing, where soft fluctuations of isospin give rise to spin-triplet superconductivity. We consider the scenario in which the pairing interaction is entirely repulsive, which stands in contrast to the typical quantum-critical pairing mechanisms. Superconductivity emerges through a "transformer" mechanism where, in the presence of an in-plane magnetic field, the incipient valley polarization converts a frequency-independent repulsion into one with a strong nonmonotonic frequency dependence. Such an interaction enables a nonzero solution for the pairing gap function that changes sign as a function of frequency. The same mechanism holds at zero field in the presence of spin-orbit coupling, providing a likely explanation for the recently observed superconductivity in bilayer graphene on the WSe2 monolayer.
引用
收藏
页数:13
相关论文
共 64 条
[1]   Quantum-critical theory of the spin fermion model and its application to cuprates: normal state analysis [J].
Abanov, A ;
Chubukov, AV ;
Schmalian, J .
ADVANCES IN PHYSICS, 2003, 52 (03) :119-218
[2]   LOW-ENERGY PROPERTIES OF FERMIONS WITH SINGULAR INTERACTIONS [J].
ALTSHULER, BL ;
IOFFE, LB ;
MILLIS, AJ .
PHYSICAL REVIEW B, 1994, 50 (19) :14048-14064
[3]   Graphene bilayers with a twist [J].
Andrei, Eva Y. ;
MacDonald, Allan H. .
NATURE MATERIALS, 2020, 19 (12) :1265-1275
[4]   Superconductivity and strong correlations in moire flat bands [J].
Balents, Leon ;
Dean, Cory R. ;
Efetov, Dmitri K. ;
Young, Andrea F. .
NATURE PHYSICS, 2020, 16 (07) :725-733
[5]  
Baranov M. A., 1992, Soviet Physics - JETP, V75, P165
[6]   Monte Carlo Studies of Quantum Critical Metals [J].
Berg, Erez ;
Lederer, Samuel ;
Schattner, Yoni ;
Trebst, Simon .
ANNUAL REVIEW OF CONDENSED MATTER PHYSICS, VOL 10, 2019, 10 (01) :63-84
[7]   Moire bands in twisted double-layer graphene [J].
Bistritzer, Rafi ;
MacDonald, Allan H. .
PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA, 2011, 108 (30) :12233-12237
[8]   GAUGE-THEORIES OF HIGH-TC SUPERCONDUCTORS [J].
BLOK, B ;
MONIEN, H .
PHYSICAL REVIEW B, 1993, 47 (06) :3454-3456
[9]   ON A NEW METHOD IN THE THEORY OF SUPERCONDUCTIVITY [J].
BOGOLJUBOV, NN .
NUOVO CIMENTO, 1958, 7 (06) :794-805
[10]   Nematicity and competing orders in superconducting magic-angle graphene [J].
Cao, Yuan ;
Rodan-Legrain, Daniel ;
Park, Jeong Min ;
Yuan, Noah F. Q. ;
Watanabe, Kenji ;
Taniguchi, Takashi ;
Fernandes, Rafael M. ;
Fu, Liang ;
Jarillo-Herrero, Pablo .
SCIENCE, 2021, 372 (6539) :264-+